trailingStrtabStringAssumeCapacity

pub fn trailingStrtabStringAssumeCapacity(self: *Builder) StrtabString {
    const start = self.strtab_string_indices.last().?;
    const bytes: []const u8 = self.strtab_string_bytes.items[start..];
    const gop = self.strtab_string_map.getOrPutAssumeCapacityAdapted(bytes, StrtabString.Adapter{ .builder = self });
    if (gop.found_existing) {
        self.strtab_string_bytes.shrinkRetainingCapacity(start);
    } else {
        self.strtab_string_indices.appendAssumeCapacity(@intCast(self.strtab_string_bytes.items.len));
    }
    return StrtabString.fromIndex(gop.index);
}